Heretofore, a number of improvements for machines capable of lifting heavy objects onto rooftops have been proposed. However, such mechanisms have had limited load capacity, limited lifting height, have been overly mechanized, and required large amounts of access. These machines require special installation or extensive setup and operation, and are expensive.
A need has thus arisen for a practical mechanism suitable for hoisting a heavy, bulky object, such as for example, an air conditioner condensing unit onto a roof, without the need for special installation or a heavy counterweight. Such a mechanism requires good reliability, reduced costs of operation and easy setup. Additionally, a need has arisen for a mechanism that can be carried up a ladder and set up by the operator. A need has still further arisen for a mechanism which can maneuver the load to its required position once it has been raised.
Still another need has further arisen for a machine that can lift and maneuver heavy and bulky loads in highly inaccessible areas on the ground and inside buildings. For example, to bypass circular staircases or maneuver large trees over turf.